Closure for containers subjected to internal pressure



July 27; 1954 J. STALLER 2,684,778 CLOSURE FOR CONTAINERS suBJEcTED TO: INTERNAL PRESSURE Filed De. 16, 1950 Ill INVENTOR.

Patented July 27, 1954 CLOSURE FOR CONTAINERS SUBJEOTED TO INTERNAL PRESSURE Jan Staller, Zurich-Erlenbach, Switzerland, as-

signor to Jan Karel Staller, Zurich-Erlenbach,

Switzerland Application December 16, 1950, Serial No. 201,108

9 Claims.

It has already been proposed to close containers subjected to internal pressure, more particularly bottles, by inserting into the container mouth provided with an elastically yielding packing ring and having a solid internal marginal lip a plate-shaped sheet metal cover with a bottom convex towards the interior of the container and with a cylindrical side wall widened at the top to form a flange and, by this side wall being widened out by a suitable implement, fixing it to the container mouth. The annular expansion of this side wall forces itself from the inside with a sealing action into the elastically yielding packing ring and at the same time bears from below against the solid marginal lip of the container mouth, so that a fluid-tight and firm seal results. For opening the closure it is only necessary for the closure cover to be pierced with a pointed implement, deformed and lifted off its seating. As each time only the relatively small and cheap cover is lost, such closures are far more economical in general use than, for instance, the commonly used crown cork closures, with which the part lost is not only considerably greater, but always contains the packing ring.

In order for some purposes, more particularly with tins, further to implify and reduce the cost of the closure, the use of a separate, elastically yielding packing ring has been discarded and the cover has simply been placed directly on the edge of the mouth of the tin, which for ensuring a better sealing effect has been coated with a thin layer of varnish.

The present invention has for its object further to perfect the known closures of the kinds referred to in such a manner that, while the closure is perfectly reliable and tight, they require the minimum amount of material and occupy the minimum amount of space, are cheap to manufacture and are convenient to open, even with considerable internal pressures.

As these closures are mass-production articles which are used in unusually large quantities, even the apparently slight economies in the single piece are of considerable importance, owing to the very large number of closures used, and make very great savings possible.

Savings in material as compared with the known constructional forms through a further reduction of the diameter of that part of the cover, which is lost in opening the closure, can hardly be efiected, as the greatest cover diameter only exceeds the internal diameter of the container mouth to a negligible extent and can therefore not be made-appreciably smaller. However, savings in material are quite possible in the vertical dimensions of the cover and more particularly in its wall thickness.

In order to give the cover bottom a high resistance to internal pressure, although the Wall thickness is small, it has hitherto been the practice, to make the cover bottom convex towards the interior of the container. Such a cover bottom loaded by the internal pressure has the tendency to flatten out, the edge of the dome seeking to Widen out. This must be prevented, since the cover in the flattened state would no longer be capable of adequately withstanding the internal pressure. Should the dome edge be supported only axially, but not radially, the flattening tendency of the bottom will cause great tensile stresses in the dome edge in the peripheral direction and, in order to be able to withstand them, the wall thickness of the cover must be made undesirably great. The conditions Will be all the more unfavourable, the flatter the doming of the bottom, although it would appear, that as flatly a domed cover bottom as possible should be aimed at for reasons of economising in material and space. Although the strength of the cover bottom may be increased by selecting a harder material, this expedient can be adopted only to a limited extent. For, on the one hand, a hard material would not easily stand up to the required widening of the side wall of the cover, which is absolutely necessary for proper fixing, while, on the other hand, a hard cover would be diificult to pierce and conse uently render the opening of the closure more difficult.

The known closures do not make provision for a sufficiently firm support of the dome edge. With them the edge either bears against the inside of the elastically yielding packing ring, into which it can penetrate, in so far as its own stability does not prevent it from doing so, or it is not supported radially at all and will project freely. In both cases it must therefore be made relatively heavy, so as not to become unduly deformed under the action of the internal pressure and to prevent the flattening of the bottom.

With these considerations in mind the inventor has come to the conclusion, that it is possible to obtain considerable economies, if provision be made for the dome edge of the cover bottom to bear in the closed position radially unyieldingly against a firm abutment surface of the container neck, which is substantially parallel to the axis. The present invention is based on this idea.

The invention is illustrated in the accompanying drawing, in which Figs. 1, 3 and 4 show different constructional examples in axial section,

3 whilst Fig. 2 is a detail of Fig. 1 i'n the loose state.

Referring to Figs. 1 and 2, l is the container wall, for instance a bottle neck of rigid material. The mouth of the container is provided with an inwardly projecting marginal lip 2. This lip has an upwardly conically tapering jointing surface 3 and a plane upper bounding surface It which is sunk with respect to the end surface 5 of the container neck. Immediately below the marginal lip 2 and forming a continuation of its conical jointing surface 3 the container neck I has a substantially cylindrical abutment surface 6. The cover 75 of stiff, yet deformable material, preferably of sheet metal, has a bottom it of fiat dome shape, which is convex towards the interior of the container, a side wall which bounds it and extends cylindrically upwards and at the top a flange 8, into which the side wall 9 widens at its upper edge. In the undeformed state, as shown in Fig. 2, the cover l can be inserted from above into the opening of the marginal lip 2, until its flange 8 lies on the surface 4, in which position it is entirely sunk below the end surface 5 cf the container neck I.

In this position, by means of suitable expanding implements, for instance by means of the jaws l l which are radially movable and may also be rotatable about the closure axis and which are provided with recesses l5 and widening projections E2, the side wall 9 of the cover I can be expanded in such a manner that a bulge E3 in the form of an annular lip results. This bulge will bear on the one hand from below against the conical jointing surface 3 of the annular lip Z; and on the other hand it will bear with the marginal edge id of the domed cover bottom it radially against the cylindrical solid abutment surface of the container neck Preferably, the axial internal diameters of the jaw recesses 55 will be made somewhat smaller than the corresponding axial dimensions of the annular lip 2 including the cover walls covering it, so that during the expanding operation the marginal lip '2 will be firmly clamped in the axial direction between the flange 8 and the bulge [3 of the cover 7. After the expanding operation has been completed, the expanding implement H is removed.

On the internal pressure of the container acting on the cover bottom ill, the cover I will be mainly forced upward by it, the conical upper side of the bulge l3 pressing against the conical jointing surface 3 of the neck l and thereby exerting a good tight-jointing action. Under the action of the internal pressure the bottom it seeks to flatten out and give its peripheral edge M a greater diameter. This is however not possible, as this edge bears radially at 6 against the firm abutment surface of the unyielding neck, which is parallel to the axis. The otherwise unavoidable high tensile stressing of the dome edge will thereby be greatly reduced, so that it becomes possible to make the bottom it considerably thinner, without having to fear its deformation by the internal pressure. For the same reason the dome may be made flatter than would be otherwise permissible. Experience has shown, that the height of the dome, It, need never be greater than 30% of the dome diameter d, but it can in most cases be reduced considerably below this value.

The firm radial support of the edge M of the bottom rim and the consequently greatly reduced danger of the bottom ll) flattening out provides the further important advantage, that a spreading of the deformation of the bottom to the actual tight-jointing part of the cover at 3 is prevented. It has been found, that in the previously known constructional forms the deformation of the edge of the cover bottom, caused by the internal pressure, is also transmitted to the conical jointi g surface and there detrimentally affected the requisite close contact. This not infrequently resulted in the closure becoming leaky, even if there should have been no complete flattening of its domed shape through the internal pressure.

As the flange 8 of the cover is sunk in the top end 5 of the container neck I, it would appear to be effectively protected against injury and undesired loosening during transport, where the containers are frequently piled directly on one another.

Not infrequently cases occur, in which the full internal pressure by no means already develops during the closing of the container, but only reaches its full strength later. Thus, for instance, in the pasteurising of beer, where its value temporarily rises to many times the initial value. Particularly in these cases it is highly desirable to obtain already during the closing operation powerfully springing clamping of the marginal lip 2 by the flange 8 and the bulge l3 in the axial direction. This can be suitably effected by making the marginal lip 2 resilient in the axial direction.

Figs. 3 and 4 show constructional examples of this kind.

According to Fig. 3 the marginal lip 2' is made in the form of an independent annular insertion of a sufliciently solid, but slightly resilient material of greater elasticity than the container neck I itself and is permanently connected with the latter in a fluid-tight manner. As material for the insertion 2 artificial substances which are plastic in the heated state are eminently suitable, especially polyvinylchloride, both owing the their properties as regards strength and elasticity and on account of their easy applicability and chemical resistivity.

The elastic forces of the annular insertion 2' clamped between the flange 8 and the bulge 13 so as to be axially resilient will prevent any detrimental loosening, even if the internal pressure of the container should have temporarily sunk below its maximum or have even completely failed.

Another constructional form having analogous efiect, which is particularly suitable for containers made of sheet metal or some similar stiff material, is shown in Fig. 4. In this case the marginal lip 2" is formed by constricting the container neck. The container wall 28 first of all merges into the abutment part [6 which is substantially parallel to the axis and of which the conical jointing part l8 forms the continuation, the latter part itself merging into the narrowest part H of the neck, which is provided with a flange i3 extending radially outwards. This arrangement has the characteristic feature, that the tight-jointing surface 3 is located between the abutment surface 4 for the cover flange 8 and the place where the abutment part iii merges into the container wall 29. The flange it together with the narrowest part ll of the neck on the one hand and the abutment part it with the container wall 26 on the other hand form two strong and rigid stifienings, between which is located the tight-jointing part l8 which makes a certain axial resilience possible. Owing to its being stilfened on both sides, it permits of the requisite elastic bending, but at the same time presents a high resistance to the stresses due to the internal pressure, so that the wall of the neck can be made relatively thin with a consequent saving in the cost of construction.

I claim:

1. A closure arrangement comprising, in combination, a container having hollow neck locatcd about a predetermined axis, id neck hav ing a lower portion provider with an inner face located at a predetermined radial distance from said axis and said neck having an upper portion.

' provided with an annular top face having inner periphery located. adjacent said and an outer periphery located distant from said axis, an inner face located at a lesser radial distance from said axis than said predetermined radial distance and extending downwardly from inner periphery of said top face, and a conical bottom face extending downwardly toward said lower neck portion and increasing in diameter as it approaches said lower neck portion, upper neck portion being resiliently yieldable a direction parallel to said axis and sai lower neck portion being substantially rigid; and a clcsure member having an annular top flange located against said top face of said upper neck portion, a tubular portion extending downwardly rom said top flange and being located about said axis and opposite said inner face of said upper neck portion, a conical portion extending downwardly from said tubular portion toward said lower neck portion, increasing in diameter as it approaches said lower neck portion, engaging said conical bottom face of said upper neck portion, and said closure member having an outer peripheral portion located at the bottom of said conical portion and engaging said inner face of said lower neck portion, said closure member having a dished bottom wall extending downwardly from said peripheral portion of said closure member, having an outer concave top face, and having an inner convex bottom face directed toward the interior of said container.

2. A closure arrangement comprising, in combination, a container having a hollow neck located about a predetermined axis, said neck having a lower portion provided with an inner face located at a predetermined radial distance from said axis and said neck having an upper por tion provided with an annular top face having inner and outer peripheries respectively located adjacent and distant from said axis, an inner face located at a lesser radial distance from said axis than said predetermined radial distance, and a conical bottom face extending downwardly toward said lower neck portion and increasing in diameter as it approaches said lower neck portion, said upper neck portion being resiliently yieldable in a direction parallel to said axis and said lower neck portion being substantially rigid, said neck having a top face located above said top face of said upper neck portion; and a closure member having an annular top flange located against said top face of said upper neck portion, a tubular portion extending downwardly from said top flange and being located about said axis opposite said inner face of said upper neck portion, a conical portion extending downwardly from said tubular portion toward said lower neck portion, increasing in diameter as it approaches said lower neck portion, engaging said conical bottom face of said upper neck portion, and said closure member having an outer peripheral portion located at the bottom of said conical portion and engaging said inner face of said lower neck portion, said closure member having a dished bottom wall extending downwardly from said peripheral portion of said closure member, having an outer concave top face, and having an inner convex bottom face directed toward the interior of said container, said top flange of said closure member having a thickness which is not greater than the distance between said top face of said neck and said top face of said upper portion of said neck.

3. A closure arrangement as defined in claim 1 and wherein said lower neck portion forms an integral part of the neck of the container. said neck of said container being formed above said lower neck portion with an internal annular groove, and said upper neck portion being in the form of an independent ring mounted in said groove.

4. A closure arrangement as defined in claim 3 and wherein said independent rin is made of polyvinyl chloride.

5. A closure arrangement as defined in claim 3 and wherein said independent ring is made of an elastic yieldable material which is more yieldable than the remainder of said neck of said container.

6. A closure arrangemnet as defined in claim 1 and wherein said upper neck portion is integral with and forms an extension of said lower neck portion.

7. A closure arrangement as defined in claim 1 and wherein said upper neck portion is integral with and forms an extension of said lower neck portion, said upper neck portion having the same thickness as said lower neck portion and providing th container with a free external annular space located about said axis and about said upper neck portion.

8. A closure arrangement as defined in claim 7 and wherein said container is made of a metal and is rigid except at said upper neck portion thereof.

9. A closure arrangement as defined in claim 8 and wherein said container widens out immediately below said lower neck portion.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 625,055 Painter May 16, 1899 639,068 Lorenz Dec. 12, 1899 658,588 Reynolds Sept. 25, 1900 745,380 Perry Dec. 1, 1903 889,872 Conrad June 2, 1908 1,845,078 Draper et a1. Feb. 16, 1932 2,028,107 Shanor Jan. 14, 1936 2,214,399 Benson Sept. 10, 1940 2,451,599 Wiltse Oct, 19, 1948 FOREIGN PATENTS Number Country Date 529,727 France Sept. 15, 19 1 

